Field of the Invention
The invention relates to an electronic apparatus and an operation method thereof, and particularly relates to a wireless communication apparatus and a method for improving a specific absorption ratio thereof.
Description of Related Art
Along with advance and development of wireless communication technology, mobile wireless communication apparatuses have been widely used in people's daily life. Each of the mobile wireless communication apparatuses has an antenna for transmitting and receiving wireless signals, though electromagnetic waves emitted by the antenna may be harmful to human health. Therefore, federal communications commission (FCC) specifies a specific absorption ratio (SAR) of the mobile wireless communication apparatuses, so as to limit radiated energy or a maximum of the amount of radiation of the mobile wireless communication apparatuses to avoid the electromagnetic waves emitted by the antenna from jeopardizing human health. The SAR refers to electromagnetic wave energy absorbed by unit mass within a unit time. In other words, the higher the SAR is, the greater the electromagnetic waves emitted by the antenna do harm to human body.
However, in order to make the SAR to be complied with a test specification, most of the conventional wireless communication apparatuses just reduce a total radiation power, so as to maintain the SAR within a safe test range. However, along with decrease of the total radiation power, a transmission distance of the electromagnetic wave is accordingly decreased, which influences the communication quality of the electronic apparatus. Alternatively, the conventional mobile wireless communication apparatus may change a structure of the antenna to make the SAR to be lower than the specification, though such method probably occupies a larger volume. Alternatively, the conventional mobile wireless communication apparatus may decrease the SAR by adding an extra circuit, though such method is liable to decrease a whole performance of the antenna or cause interference. Therefore, how to satisfy the safety specified by the SAR while considering the communication quality of the mobile wireless communication apparatus has become a major problem faced in design of the mobile wireless communication apparatus.